r/bin/python. Change it to python3 (or python2) explicitly.
mangling shebang in /usr/libexec/mc/extfs.d/bpp from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/iso9660 from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/hp48+ from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uarc from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uzoo from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/rpm from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/lslR from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uar from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/gitfs+ from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/ulha from /bin/sh to #!/usr/bin/sh
BUILDSTDERR: *** ERROR: ambiguous python shebang in /usr/libexec/mc/extfs.d/uc1541: #!/usr/bin/python. Change it to python3 (or python2) explicitly.
mangling shebang in /usr/libexec/mc/extfs.d/audio from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/trpm from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/urar from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/changesetfs from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uha from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/u7z from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/patchsetfs from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uarj from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/ualz from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/extfs.d/uace from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/doc.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/video.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/archive.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/package.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/sound.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/misc.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/text.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/image.sh from /bin/sh to #!/usr/bin/sh
mangling shebang in /usr/libexec/mc/ext.d/web.sh from /bin/sh to #!/usr/bin/sh
BUILDSTDERR: *** WARNING: ./usr/libexec/mc/mc-wrapper.sh is executable but has empty or no shebang, removing executable bit
BUILDSTDERR: *** WARNING: ./usr/libexec/mc/mc.sh is executable but has empty or no shebang, removing executable bit
BUILDSTDERR: *** WARNING: ./usr/libexec/mc/mc.csh is executable but has empty or no shebang, removing executable bit
BUILDSTDERR: *** WARNING: ./usr/libexec/mc/mc-wrapper.csh is executable but has empty or no shebang, removing executable bit
BUILDSTDERR: *** WARNING: ./etc/profile.d/mc.sh is executable but has empty or no shebang, removing executable bit
BUILDSTDERR: *** WARNING: ./etc/profile.d/mc.csh is executable but has empty or no shebang, removing executable bit
mangling shebang in /etc/mc/edit.indent.rc from /bin/sh to #!/usr/bin/sh
RPM build errors:
BUILDSTDERR: error: Bad exit status from /var/tmp/rpm-tmp.myTH1J (%install)
BUILDSTDERR:     Bad exit status from /var/tmp/rpm-tmp.myTH1J (%install)
Child return code was: 1
EXCEPTION: [Error()]
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/mockbuild/trace_decorator.py", line 96, in trace
    result = func(*args, **kw)
  File "/usr/lib/python3.6/site-packages/mockbuild/util.py", line 626, in do
    raise exception.Error("Command failed: \n # %s\n%s" % (command, output), child.returncode)
mockbuild.exception.Error: Command failed: 
 # bash --login -c /usr/bin/rpmbuild -bb --target riscv64 --nodeps /builddir/build/SPECS/mc.spec